Plica syndrome is an irritation of a small portion of tissue in the knee joint that is part of the joint capsule (synovial membrane). The synovial membrane produces fluid that helps to keep the knee joint lubricated. When this tissue on the inside of the kneecap becomes irritated, it results in knee pain and tenderness to touch. Often the result of overuse, plica syndrome also may result from a direct-hit injury. Plica syndrome is most often treated with physical therapy to improve mobility and strengthening at the knee to decrease tension and irritation.

What is Plica Syndrome?

Plica syndrome is an irritation of a portion of the synovial membrane in the knee. The synovial membrane encloses the knee joint and contains the fluid that keeps the joint lubricated. Plica syndrome results when the synovial lining becomes irritated, typically the result of repetitive friction to the tissue, or in some cases a direct hit to the knee that traumatizes the tissue. As a result, this tissue will become thick and painful. Repetitive friction is due to abnormal forces at the knee, most likely in the kneecap and surrounding musculature, or may be caused by muscular weaknesses or structural abnormalities at the hip or foot, which place increased tension on the knee. Plica syndrome also can be caused or made worse by increased activities.

Plica syndrome may result from a combination of several different factors, including:

Decreased mobility of the kneecap

Quadricep (front of the thigh) muscle or hip muscle tightness

Muscular imbalances in the quadricep, hamstring (back of the thigh), or hip muscles

How Is It Diagnosed?

Your physical therapist will review your medical history and complete a thorough examination of your knee. The goals of the initial examination are to assess the degree of the injury and determine the cause and contributing factors to your injury. Your physical therapist will assess the mobility and strength of both lower extremities, including your foot and ankle as well as your knee and hip. Most often your physical therapist will be able to feel a thickened piece of irritated tissue on your knee.

It is also common for your physical therapist to perform a movement assessment, which may include watching you walk, step onto a stair, squat, or balance on one leg.

Your physical therapist also may ask questions about your daily activities, exercise regimens, and footwear to identify other contributing factors.

Imaging techniques, such as X-ray or MRI, are often not initially obtained. In the case of persistent pain, your physician may decide to obtain an MRI to help identify the source of your pain.

Whether your pain was caused by a single injury or repetitive irritation, your initial examination as well as treatment will be similar. Initially, the primary goals are to calm down the inflamed tissue. Your physical therapist will then address any underlying issues that may cause continued tissue irritation.

How Can a Physical Therapist Help?

You and your physical therapist will work together to develop a plan to achieve your specific goals. To do so, your therapist will select treatment strategies in any or all of the following areas:

Pain. Many pain-relief strategies may be implemented, such as applying ice to the area or using therapies like iontophoresis (a medicated patch placed on the skin that is electrically charged and used to decrease pain and inflammation). Your physical therapist will work with you to reduce your pain as much as possible without the use of pain medication, including opioids.

Range of motion. Your knee, hip, or foot may be moving improperly, causing increased strain at the front of the knee. Self-stretching and manual therapy techniques (massage and movement) applied to the lower body to help restore and normalize motion in the knee, hip, and foot can decrease this tension.

Manual therapy. Your physical therapist may apply hands-on treatments to move your muscles and joints in order to improve their motion and strength, most likely in your knee and hip. These techniques often address areas that are difficult to treat on your own.

Muscle strength. Muscular weaknesses or imbalances can result in abnormal forces being applied to the front of the knee. Based on your specific condition, your physical therapist will design a safe, individualized, progressive resistance program for you, likely including your core (midsection) and lower extremities, and concentrating on the muscles surrounding the hip and knee. These exercises may be completed in different positions such as lying down, sitting, or standing. Your physical therapist will choose what exercises are right for you, based on your age and physical condition.

Functional training. Once your pain, strength, and motion improve, you will need to safely transition back into more demanding activities. To minimize the tension on the knee and your risk of repeated injury, it is important to teach your body safe, controlled movements. Based on your goals and movement assessment, your physical therapist will create a series of activities that will help you learn how to use and move your body correctly to safely perform the tasks required to achieve your goals.

Education. Your physical therapist will work with you to identify and change any external factors causing your pain, such as exercise selection, the amount of exercise you do, or your footwear. Your physical therapist will assess your current condition and lifestyle, recommend improvements, and develop a personal exercise program to help ensure a pain-free return to your desired activities.

Physical therapy promotes recovery from plica syndrome by addressing all contributing factors, such as pain and any lack of strength, flexibility, or body control. Your physical therapist also may recommend a period of relative rest, then carefully guide your progression back to normal activity levels.

When Surgery Is Required

If your plica syndrome pain does not improve following several weeks of physical therapy, arthroscopic surgery may be required. Your surgeon will make small incisions in the front of the knee and remove the irritated tissue. Following surgery, your initial rehabilitation will focus on decreasing pain and restoring mobility and strength. Your physical therapist will then address specific factors that caused your plica to become irritated, in order to minimize the risk of further injury. As you progress, your physical therapist will help you systematically reintroduce activities, including stair climbing, squatting, and desired recreational

Can this Injury or Condition be Prevented?

Maintaining appropriate lower-extremity (leg, ankle, foot) mobility and muscular strength, and paying particular attention to your exercise routine—especially changes in an exercise activity and the volume of exercises performed—are the best methods for preventing plica syndrome. Some patients with abnormalities in knee structure, however, may be more susceptible to developing plica syndrome.

If you are experiencing plica syndrome, your physical therapist will help guide you through a rehabilitative process based on your unique condition that will progressively reintegrate more demanding activities into your routine without overstraining your knee. Keep in mind that returning to activities too quickly often leads to persistent pain, and makes the condition more difficult to fix. Once you have completed your rehabilitation, your newfound strength, flexibility, and knowledge may help you prevent the syndrome from recurring.

Real Life Experiences

Sara is a 15-year-old high school sophomore and soccer athlete. Three weeks ago, Sara began experiencing knee pain during her team’s preseason training runs. She was able to complete the preseason running and weight-lifting activities, but her pain persisted. Her team is now 2 weeks into the regular season; Sara continues to experience knee pain, which limits her ability to perform well with the team. Away from the soccer field, she also experiences pain when walking and climbing stairs.

Sara and her parents are concerned about her persistent knee pain, and she worries about her ability to continue to play soccer this season. They consult her physical therapist.

Sara's physical therapist conducts a comprehensive examination, assessing her motion, strength, balance, and movement mechanics. He gently touches the front, sides, and back of Sara’s knee to identify the exact location of her pain. Based on these findings, he diagnoses the possibility of plica syndrome. He consults her physician, who orders an MRI to confirm the diagnosis. The test results confirm that Sara is experiencing plica syndrome.

Sara, her family, and her physical therapist work together to establish short- and long-term goals and identify immediate treatment priorities, including icing and mobility exercises to decrease her pain, as well as gentle strengthening exercises. Her physical therapist also identifies appropriate soccer activities to continue—and to avoid—to help Sara heal more quickly. Sara is also prescribed a home-exercise program consisting of a series of activities to perform daily to help her recovery.

Together, they outline a 4-week rehabilitation program for plica syndrome. Sara visits her physical therapist 2 times each week; he assesses her progress, performs manual therapy techniques, and advances her exercise program as appropriate. He also advises her when it is appropriate to resume additional soccer activities, and establishes a day-by-day plan to help her safely progress. Sara also performs an independent daily exercise routine at home, including stretching and strengthening activities.

After 4 weeks of hard work, Sara is able to complete all of her daily and soccer activities without pain. She looks forward to competing with the team next season at the top of her form!

This story was based on a real-life case. Your case may be different. Your physical therapist will tailor a treatment program to your specific case.

What Kind of Physical Therapist Do I Need?

All physical therapists are prepared through education and experience to treat plica syndrome. However, you may want to consider:

A physical therapist who is experienced in treating people with plica syndrome. Some physical therapists have a practice with an orthopedic or musculoskeletal focus.

A physical therapist who is a board-certified clinical specialist in orthopedics or who completed a residency or fellowship in orthopedic or sports physical therapy. This physical therapist has advanced knowledge, experience, and skills that may apply to your condition.

You can find physical therapists who have these and other credentials by using Find a PT, the online tool built by the American Physical Therapy Association to help you search for physical therapists with specific clinical expertise in your geographic area.

General tips when you're looking for a physical therapist (or any other health care provider):

Get recommendations from family and friends or from other health care providers.

When you contact a physical therapy clinic for an appointment, ask about the physical therapists' experience in helping people with plica syndrome.

During your first visit with the physical therapist, be prepared to describe your symptoms in as much detail as possible, and describe what makes your symptoms worse.

Further Reading

The American Physical Therapy Association (APTA) believes that consumers should have access to information that could help them make health care decisions and also prepare them for their visit with their health care provider.

The following articles provide some of the best scientific evidence related to physical therapy treatment of plica syndrome. The articles report recent research and give an overview of the standards of practice both in the United States and internationally. The article titles are linked either to a PubMed* abstract of the article or to free full text, so that you can read it or print out a copy to bring with you to your health care provider.

* PubMed is a free online resource developed by the National Center for Biotechnology Information (NCBI). PubMed contains millions of citations to biomedical literature, including citations in the National Library of Medicine’s MEDLINE database.

Revised by James Zachazewski, PT, DPT. Authored by Allison Mumbleau, PT, DPT. She is a board-certified clinical specialist in sports physical therapy. Reviewed by the MoveForwardPT.com editorial board.